Aminophenol derivatives and photographic developers containing them



Patented Apr. 24, 1945 AMINOPHENOL DERIVATIVES AND PHOTO: GRAPHIC DEVELOPERS CONTAINING Verne H. Reckmeyer and August H. Brunner, Jr., Binghamton, N. Y., aasignors to General Aniline & Film Corporation, New York, N. Y., a corporation of Delaware No Drawing. Original application May 20, 1941,

are characterized by improved solubility.

Serial N 0. 394,286. Divided and this application January 4, 1944, Serial No. 516,976

3 Claims. (01. 260-574) The present invention is concerned with new chemical compounds and more particularly with new derivatives of methyl amino phenols and photographic developers which contain the same.

It is well known in the photographic art that various aminophenols and polyhydroxy compound are suitable for use as photographic developers. One of the most common of these compounds is vmonomethyl p-amino phenol sulphate which has been marketed under the trade name Metol." This particular developer, however, is not too greatly soluble in aqueous sodium sulfite solutions and it is therefore impossible to prepare developing solutions of extremely high concentration which may be diluted at a later date-by the user.

With thi prior art in view, it is accordingly one object 01! the present invention to provide new derivatives of monomethyl amino phenols, which A further object is to provide new derivatives of monomethyl p-amino phenol. v

Another-object is to providesuch compounds suitable for use as photographic developers.

An additional object is the provision or photo graphic developers which include the new amino phenol derivatives. Y

Other objects and advantages of this invention will bereadily apparent from the following speciflcation.

It has now been found that the above objects are accomplished by the preparation and use of amino phenol derivatives which are reaction prodnets of a monomethyl amino phenol with either sulphur dioxide or sulfamic acid. These new compounds are characterized by their ready solubility and are accordingly extremely suitable for the preparation of concentrated liquid photographic developers. In order that those persons skilled in the art may fully understand the nature and scope of this invention, a detailed description of the method of preparation of these new compounds and. of their use in developing solutions may be further extracted with diethyl. ether and the whole amount of free base dissolved in diethyl ether. The composition is dried with anhydrous sodium sulfate. Dry sulphur dioxide is then passed into the solution until precipitation is complete. The solid is filtered, washed with di-ethyl ether, and dried over sodium hydroxide in vacuo to remove excess sulphur dioxide.

The resulting compound has a melting point of about 95 C. and decomposes at 103 to 104 C.

-The compound is a brownish-yellow or buffcolored powder. The exact constitution of this reaction product is not definitely known although it appears that it might be designated either as monomethyl p-amino phenol N-sulfinic acid, or as the sulphur dioxide addition product of monomethyl p-amino phenol.

. The sultamic acid derivative, on the other hand,

is prepared by the addition of sulfamic acid to the free base.

phenol may hol and treated with 24 g. of sulfamic acid (ransom). One gram of sodium sulfite is added Thus 62 g. of monomethyl p-amino in order to lighten the color and avoid oxidation and the mixture is then distilled at about 15 mm.

' pressure until the volume has been reduced to 100 light tan crystals.

cc. The resulting solid is then washed with di oxane. This product has a melting point of 105 to 106 C. and in general appearance resembles The corresponding compounds from monomethyl ortho amino phenol can be prepared in a substantially analogous manner.

The new derivatives prepared in the above mam ner are quite readily soluble in aqueou sodium sulfite solutions particularly in comparison with the previously known sulfate compound. This improved solubility in sul flte solutions is extremely surprising since the ordinary water solubility of the new compounds is substantially similar to that 01' the sulfate. The relative solubility may be dissolved in 250 cc. of ethyl alco-' phur dioxide addition compound of monomethyl' p-amino phenol in solutions of sodium sulfite.

The para. compounds show a. particularly improved solubility. v

Table of solubilittes Solubility at 23 0. golzlentzcrongeg- Mono methyl Mono methyl Mono methyl 50mm p-amino phenol p'amlnophcnolp-cmino bone]- 80. compound sulfamatesulfate otol) Per cent Per cent Per cm! Per cent Because of the increased solubility of these new compounds it is possible to make up a more concentrated photographic developing solution than was hitherto possible with 'Metol. The concentrated solution can then be diluted by the user. In this way the volume of the solution which is sold is much Smaller than would otherwise be the case and the cost of handling and shipping such a developer is therefore reduced. Suitable developingv compositions according to the present invention are the following:

Formula! Mono methyl p-amino phenol SO: compound I gms Sodium sulflte gms Water to m e M 1000 For use dilute with a, 10% solution of sodium sulflte and develop as follows:

Developing time 1 Dilution g 523F331? 1:7 15 min. at 68 F. 1-15 18 min. st 68' F. 1:30 22 min. at 68 1'. 1:60 20 min. at 68 F.

Formula II Mono methyl p-amino phenol sulfamate ma". 30 Sodium sulfite gms Water to mak cc 1000 For use dilute one part with nine parts of 10%-\ sodium sulfite solution. Develop Agra. Superpanfl 

